Nothing Special   »   [go: up one dir, main page]

EP1872116B1 - Method using an electrochemical sensor and electrodes forming said sensor - Google Patents

Method using an electrochemical sensor and electrodes forming said sensor Download PDF

Info

Publication number
EP1872116B1
EP1872116B1 EP06743351A EP06743351A EP1872116B1 EP 1872116 B1 EP1872116 B1 EP 1872116B1 EP 06743351 A EP06743351 A EP 06743351A EP 06743351 A EP06743351 A EP 06743351A EP 1872116 B1 EP1872116 B1 EP 1872116B1
Authority
EP
European Patent Office
Prior art keywords
electrode
self
current
working
cleaning
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Not-in-force
Application number
EP06743351A
Other languages
German (de)
French (fr)
Other versions
EP1872116A2 (en
Inventor
Eduardo Santoli
Philippe Rychen
Jean Gobet
Remo Pfändler
Paul Bitsche
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Adamant Technologies SA
Hach Lange SARL
Original Assignee
Adamant Technologies SA
Zuellig AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Adamant Technologies SA, Zuellig AG filed Critical Adamant Technologies SA
Priority to EP06743351A priority Critical patent/EP1872116B1/en
Publication of EP1872116A2 publication Critical patent/EP1872116A2/en
Application granted granted Critical
Publication of EP1872116B1 publication Critical patent/EP1872116B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416—Systems
    • G01N27/4163—Systems checking the operation of, or calibrating, the measuring apparatus
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416—Systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/18—Water

Definitions

  • the present invention relates to electrochemical sensors for measuring the concentration of a chemical substance in an aqueous medium.
  • Such devices find a particularly interesting, but not exclusive, application to the detection of the amount of oxygen dissolved in water, particularly in the basins of the treatment plants.
  • the invention relates to a method of self-cleaning an electrochemical sensor.
  • Electrochemical sensors of the type mentioned above necessarily include a working electrode, a reference electrode and a counter-electrode.
  • Another type of such sensors is also known which further comprises an electrode, called generator, and its counter-electrode.
  • generator an electrode
  • counter-electrode an electrode that is to create changes in the concentration of species present in solution
  • the pH of the solution can be modified locally by applying a current to the generator electrode.
  • Cathodic current will lead to the production of OH- ions (the pH will then become more basic) and, conversely, an anode current will lead to the production of H + ions (the pH then becomes more acidic).
  • a counter-electrode associated with the generating electrode, a counter-electrode associated with the working electrode and a reference electrode are necessary for producing a complete sensor.
  • Electrodes of very small dimensions, not only because this makes it possible to reduce the space between the generating electrode and the working electrode, but also because the effects of fluid turbulence at the cell level are minimized.
  • Such small electrodes are called indifferently, in the remainder of the description, "micro-electrodes” or “micro-disks”, the latter name being due to the fact that the microelectrodes are most often circular.
  • the document WO 02/095387 discloses a sensor as mentioned above and shown in FIG. figure 1 . It uses an electrically conductive substrate 10, advantageously made of doped silicon and whose lower face is covered with a metallization layer 11. Its upper face is covered with a passivation layer 12 formed of a stack of two sub-layers of SiO 2 and Si 3 N 4 , known to have excellent stability in aqueous medium.
  • the passivation layer 12 is provided with circular openings 13. Its upper face and the openings 13 are covered with a conducting layer 14 bearing the reference 16 when it is on the layer 12 and the reference 18 when it forms a micro -disque resting in one of the circular openings 13.
  • the layer 14 is pierced with a network of annular openings 19 each surrounding one of the micro-discs 18.
  • the layer 16 forms the generating electrode while all the micro-discs 18, electrically connected in parallel to each other, together constitute the working electrode of the system.
  • Electrochemical sensors find an interesting application in the measurement of the concentration of dissolved oxygen in the treatment plant basins.
  • the wastewater is treated with bacteria that are very sensitive to this dissolved oxygen concentration.
  • the information provided by the sensors makes it possible to regulate a system of aeration of the basin so that the conditions are favorable to the bacteria.
  • the sensors on the market do not give satisfactory results, in particular because of various contaminations and organic matter which is deposited on the electrode, thus modifying its sensitivity.
  • conventional sensors it is generally used to combat contamination, mechanical methods such as forced air, pressurized water jet, abrasion; methods that all have a lot of disadvantages.
  • One of the aims of the present invention is therefore to solve the aforementioned problem by proposing a sensor whose accuracy is not dependent on the phenomena of contamination.
  • the invention relates to a method for self-cleaning a working electrode of an electrochemical sensor comprising, on the one hand, a working electrode of the micro-disk type and its counter-electrode, and a reference electrode connected to a potentiostat, and, secondly, a boron-doped diamond generating electrode and its counter-electrode connected to a current source. All of these electrodes are, in addition, connected to a control and measurement electronics.
  • the self-cleaning process may precede a method of measuring at least one species dissolved in an aqueous medium.
  • Working and reference electrodes are disconnected from their power supply during the self-cleaning step.
  • a negative voltage refers to a cathode potential and a positive voltage refers to an anode potential.
  • the Figures 2 and 3 represent a chip 21. It has an electrically conductive substrate 20 which is in the form of a plate, for example square, typically 2 to 10 mm side and 0.5 mm thick. This plate is advantageously made of silicon made conductive by doping according to techniques well known to those skilled in the art. It is placed on a support 35, made of insulating polymer.
  • the substrate 20 is pierced on its upper face with a regular network of substantially cylindrical cavities 22, with an axis perpendicular to the plane of the substrate.
  • these cavities have a diameter of 2 to 20 microns, a depth of 2 to 20 microns and are spaced from each other by about 40 to 400 microns.
  • each cavity 22 is partially covered by a metallization 23 which has a diameter 0.5 to 5 ⁇ m smaller than that of the cavity 22.
  • the set of metallizations 23 constitutes the working electrode of the system.
  • a metal deposit can be made on the metallizations 23 by galvanic growth.
  • the upper face of the substrate 20 is covered with an insulating layer 25, called passivation, which is formed, for example, of a stack of two sublayers of SiO 2 and Si 3 N 4 and has a thickness of about 0.1 to 1 ⁇ m.
  • This layer is pierced with a regular network of circular through openings 27 centered on the cavities 22, of smaller diameter than the cavities.
  • a generating electrode 30, which may be made of diamond, arranged around the measurement electrodes according to the teaching of the document WO 02/095387 and demand EP 04 405039.1 .
  • the electrode 30 is formed of a thin layer of diamond made conductive by doping, which is pierced with circular openings 26 of diameter greater than that of the cavities 22 and arranged so that each opening 26 is concentric to a micro-electrode.
  • the diamond used to form the electrode is doped with boron.
  • the working and generating electrodes may be made according to the structure represented on the figure 1 .
  • the electrode 30 When the electrode 30 is energized, it makes it possible to generate strongly oxidizing species such as hydroxyl radicals. As explained in the introduction, these may have a detrimental effect on polymer coatings 34, for example silicone, generally deposited on the electrical contacts of the generating electrode, more precisely at the interface between the coating 34 and the diamond layer 30 in contact with the medium.
  • strongly oxidizing species such as hydroxyl radicals.
  • these may have a detrimental effect on polymer coatings 34, for example silicone, generally deposited on the electrical contacts of the generating electrode, more precisely at the interface between the coating 34 and the diamond layer 30 in contact with the medium.
  • a protective layer 31 is deposited on the diamond generating electrode 30 prior to the coating 34, so that there is no longer a direct interface between the coating 34 and the diamond layer 30.
  • protective layer is made of a material inorganic electrically insulating, such as SiO 2 or Si 3 N 4 , which, moreover, have excellent stability in aqueous medium.
  • the layer 31 has a thickness of between 0.1 and 0.5 ⁇ m. It is deposited and shaped according to the techniques known to those skilled in the art.
  • the protective layer 31 is located at the periphery of the electrode 30 and forms a frame so as to cover the elements to be protected. It comprises openings 32 necessary for the electrical connection with the generating electrode 30.
  • a metal contact frame not shown, can be deposited, by evaporation, on the protective layer 31 which is provided with several openings 32.
  • the contact frame can also be made separately and then bonded to the electrode 30, at the openings 32, by a conductive adhesive.
  • the polymer coating 34 is then deposited on the electrical contacts and, if there is one, on the contact frame. As can be seen on the figure 3 the coating overflows over the protective layer 31 and also covers the lateral surfaces of the chip 21.
  • the chip 21 described above therefore comprises a working electrode (set of metallizations 23) and a generating electrode 30. It is integrated in a measuring head 38 shown, in section, at the figure 4 .
  • the measuring head 38 further comprises a counter-electrode for the working electrode 40 and a reference electrode 42.
  • the head 38 is made of a non-metallic material of the non-conductive polymer type.
  • the head 38 may also include a counter-electrode for the generating electrode, but it will be understood hereinafter why it does not appear in the embodiment described.
  • the areas of the electrodes intended to be in contact with the medium to be analyzed are flush with the surface of the measuring head 38 and are located at a short distance from one another.
  • Connector elements 44 pass through the measuring head to connect the electrodes to the electronics 46 control, measurement and interface with the outside (display, recording, etc.).
  • the generator electrode and its counter-electrode are connected to a current source, while the working electrode and its counterelectrode, on the one hand, and the reference electrode, on the other hand, are connected to a potentiostat which makes it possible to impose a voltage between the electrodes and thus to measure, at a determined voltage, the current flowing between the working electrode and its counter-electrode.
  • the counter-electrode of the working electrode 40 is advantageously made of a conductive and chemically stable material, such as stainless steel, gold or platinum. Its surface is typically 100 times greater than that of the micro-disks of the working electrode 23.
  • the reference electrode 42 is chosen according to the intended application. For a measurement of the oxygen concentration in an aqueous medium, an Ag / AgCl electrode is generally preferred.
  • a layer of polymer material 34 is deposited on the edges of the electrode substrates.
  • the measuring head 38 is sealingly mounted at the end of a probe body 48, generally tubular in shape, visible on the figure 5 .
  • the head 38 is provided with positioning holes 50 which cooperate with lugs arranged in the body 48. It is thus very easy, in case of need, to replace the measuring head 38.
  • the measurement head is then fixed to the body of the probe by means of a ring 49, which is screwed on the body of the probe. the probe so as to seal the assembly.
  • the probe body 48 is made of a metallic material, such as stainless steel, and serves as a counter electrode for the generator electrode.
  • the body 48 serves as a counter electrode for the generator electrode and / or the working electrode.
  • the body 48 may also comprise a non-metallic part and a metal part, the latter being used as a counter-electrode.
  • the end of the probe body 48 which receives the measuring head 38 is inclined at an angle between 0 and 90 °, preferably between 30 and 60 °, preferably of the order of 45 °, relative to the rest of the 48.
  • the latter being immersed vertically in the liquid to be analyzed, the angle that has its end improves the hydrodynamic conditions around the measuring head 38, particularly when the medium is agitated.
  • the amperometric measurement of the dissolved oxygen concentration in an aqueous medium is performed by applying an adequate reduction potential between the working electrode and the reference electrode. A reduction current is then created proportional to the concentration of dissolved oxygen in the liquid circulating between the working electrode and its counter-electrode. The current can then be measured in the working electrode, this current being representative of the oxygen concentration of the medium.
  • a self-calibration procedure (not claimed), an example of which will be given below, makes it possible to effectively compensate the drifts due to loss of sensitivity of the working electrode.
  • This in situ procedure is based on a change in the local concentration of dissolved oxygen, obtained by means of variations of the polarization of the generating electrode which lead to the electrolysis of the water according to the reaction: 2H 2 O ⁇ O 2 + 4H + + 4th -
  • This reaction locally changes the concentration of dissolved oxygen precisely and independently of the oxygen content of the surrounding environment. Indeed, the density and duration of application of the current received by the generating electrode can control the production of oxygen.
  • the difference between the response of the working electrode before and after the oxygen production by the generating electrode makes it possible to deduce a calibration factor.
  • the latter represents the sensitivity of the sensor and provides, for a given sensor, a coefficient of proportionality between the oxygen concentration of the medium to be analyzed and the actual current measured between the working electrode and its counter-electrode.
  • the time during which the dissolved oxygen concentration is locally increased depends on the stirring conditions of the medium.
  • the electric field generated by the generating electrode can disturb the behavior of the reference electrode during the self-calibration if, during this procedure, the measurement is done simultaneously with the operation of the generator electrode.
  • the self-calibration measurement is performed just after stopping the supply of the generator electrode, on a point or by averaging the values obtained over a certain range, as will be seen below. .
  • a measurement can be made during the application of a current to the generator electrode.
  • Self-cleaning is achieved by the conjunction of several effects caused by the application to the diamond electrode of currents of different polarity and density.
  • an anode current causes H + ion production, which acidifies the aqueous medium close to the electrode.
  • scale deposits calcium carbonate, magnesium oxides
  • this type of current applied to a boron-doped diamond electrode results in the production of highly active species, such as hydroxyl radicals, which degrade organic deposits such as bio-films, and possess a biocidal activity.
  • the self-cleaning step is applied at defined intervals, so that the oxygen produced during the application of an anode current does not disturb the subsequent measurements.
  • control electronics 46 are perfectly accessible to those skilled in the art and are therefore not described here in detail.
  • Such a measurement procedure is repeated at a frequency typically of 0.5 to 5 times per minute according to the values of the parameters defined above, more particularly of 2 measurements per minute.
  • Such a self-calibration procedure is repeated at a frequency of 0.1 to 48 times per day, typically 1 time per day.
  • Such a self-cleaning procedure is repeated at a frequency of 10 to 200 times a day, typically 100 times a day.
  • an electrochemical sensor can allow self-cleaning, by preventing the oxidizing species from attacking the constituent elements of the sensor.
  • the present invention is not limited to an electrochemical sensor measuring the concentration of dissolved oxygen in a medium. Indeed, it is possible to correlate the currents measured for different species analyzed other than oxygen, for example, chlorine or ozone.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Pathology (AREA)
  • Immunology (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Molecular Biology (AREA)
  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
  • Measuring Or Testing Involving Enzymes Or Micro-Organisms (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
  • Measuring Oxygen Concentration In Cells (AREA)

Abstract

The method involves measuring a micro-disc type working electrode (23) current representing the concentration of oxygen dissolved in an aqueous medium before the current is applied to a generating electrode (30). An anodic current of preset duration is applied to the electrode (30). The working electrode`s current is measured after the current is applied to the electrode (30). A calibration factor of oxygen, dissolved in the medium, relating the oxygen concentration in the medium and a current measured between the electrode (23) and a counter electrode, is calculated from the currents. An independent claim is also included for a method for auto-cleaning of a working electrode of an electrochemical sensor.

Description

Domaine techniqueTechnical area

La présente invention se rapporte aux capteurs électrochimiques destinés à mesurer la concentration d'une substance chimique dans un milieu aqueux. De tels dispositifs trouvent une application particulièrement intéressante, mais non exclusive, à la détection de la quantité d'oxygène dissous dans de l'eau, particulièrement dans les bassins des stations d'épuration.The present invention relates to electrochemical sensors for measuring the concentration of a chemical substance in an aqueous medium. Such devices find a particularly interesting, but not exclusive, application to the detection of the amount of oxygen dissolved in water, particularly in the basins of the treatment plants.

L'invention concerne, plus particulièrement, un procédé d'auto-nettoyage d'un capteur électrochimique.More particularly, the invention relates to a method of self-cleaning an electrochemical sensor.

Etat de la techniqueState of the art

Les capteurs électrochimiques du type mentionné ci-dessus comportent nécessairement une électrode de travail, une électrode de référence et une contre-électrode. On connaît également un autre type de tels capteurs qui comportent, en outre, une électrode, dite génératrice, et sa contre-électrode. L'ajout de ces deux dernières électrodes, dont l'effet est de créer des modifications de concentration d'espèces présentes en solution, permet de contrôler localement l'environnement de l'électrode de travail.Electrochemical sensors of the type mentioned above necessarily include a working electrode, a reference electrode and a counter-electrode. Another type of such sensors is also known which further comprises an electrode, called generator, and its counter-electrode. The addition of these last two electrodes, whose effect is to create changes in the concentration of species present in solution, makes it possible to locally control the environment of the working electrode.

Par exemple, le pH de la solution peut être modifié localement par l'application d'un courant à l'électrode génératrice. Un courant cathodique entraînera la production d'ions OH- (le pH devenant alors plus basique) et, inversement, un courant anodique entraînera la production de ions H+ (le pH devenant alors plus acide). Une contre-électrode associée à l'électrode génératrice, une contre-électrode associée à l'électrode de travail et une électrode de référence sont nécessaires à la réalisation d'un capteur complet.For example, the pH of the solution can be modified locally by applying a current to the generator electrode. Cathodic current will lead to the production of OH- ions (the pH will then become more basic) and, conversely, an anode current will lead to the production of H + ions (the pH then becomes more acidic). A counter-electrode associated with the generating electrode, a counter-electrode associated with the working electrode and a reference electrode are necessary for producing a complete sensor.

On comprendra aisément qu'il est particulièrement avantageux d'utiliser, comme électrode de travail, des électrodes de très petites dimensions, non seulement parce que cela permet de réduire l'espace entre l'électrode génératrice et l'électrode de travail, mais aussi parce que les effets de la turbulence du liquide au niveau de la cellule s'en trouvent minimisés. De telles électrodes de petites dimensions sont appelées indifféremment, dans la suite de la description, "micro-électrodes" ou "micro-disques", cette dernière appellation étant due au fait que les micro-électrodes sont le plus souvent de forme circulaire.It will be readily understood that it is particularly advantageous to use, as a working electrode, electrodes of very small dimensions, not only because this makes it possible to reduce the space between the generating electrode and the working electrode, but also because the effects of fluid turbulence at the cell level are minimized. Such small electrodes are called indifferently, in the remainder of the description, "micro-electrodes" or "micro-disks", the latter name being due to the fact that the microelectrodes are most often circular.

Le document WO 02/095387 décrit un capteur tel que mentionné précédemment et représenté à la figure 1. Il utilise un substrat électriquement conducteur 10, avantageusement réalisé en silicium dopé et dont la face inférieure est recouverte d'une couche de métallisation 11. Sa face supérieure est recouverte d'une couche de passivation 12 formée d'un empilement de deux sous-couches de SiO2 et Si3N4, connu pour présenter une excellente stabilité en milieu aqueux.The document WO 02/095387 discloses a sensor as mentioned above and shown in FIG. figure 1 . It uses an electrically conductive substrate 10, advantageously made of doped silicon and whose lower face is covered with a metallization layer 11. Its upper face is covered with a passivation layer 12 formed of a stack of two sub-layers of SiO 2 and Si 3 N 4 , known to have excellent stability in aqueous medium.

La couche de passivation 12 est dotée d'ouvertures circulaires 13. Sa face supérieure et les ouvertures 13 sont recouvertes d'une couche conductrice 14 portant la référence 16 lorsqu'elle est sur la couche 12 et la référence 18 lorsqu'elle forme un micro-disque reposant dans l'une des ouvertures circulaires 13. La couche 14 est percée d'un réseau d'ouvertures annulaires 19 entourant chacune l'un des micro-disques 18.The passivation layer 12 is provided with circular openings 13. Its upper face and the openings 13 are covered with a conducting layer 14 bearing the reference 16 when it is on the layer 12 and the reference 18 when it forms a micro -disque resting in one of the circular openings 13. The layer 14 is pierced with a network of annular openings 19 each surrounding one of the micro-discs 18.

La couche 16 forme l'électrode génératrice tandis que tous les micro-disques 18, électriquement connectés en parallèle les uns aux autres, constituent, ensemble, l'électrode de travail du système.The layer 16 forms the generating electrode while all the micro-discs 18, electrically connected in parallel to each other, together constitute the working electrode of the system.

Les capteurs électrochimiques trouvent une application intéressante dans la mesure de la concentration en oxygène dissous dans les bassins de station d'épuration. En effet, les eaux usées sont traitées au moyen de bactéries qui sont très sensibles à cette concentration en oxygène dissous. L'information fournie par les capteurs permet de réguler un système d'aération du bassin pour que les conditions soient favorables aux bactéries. Cependant, les capteurs présents sur le marché ne donnent pas des résultats satisfaisants, notamment à cause de diverses contaminations et des matières organiques qui se déposent sur l'électrode, modifiant ainsi sa sensibilité. Avec les capteurs classiques, on a généralement recours, pour combattre la contamination, à des méthodes mécaniques du type air pulsé, jet d'eau sous pression, abrasion; méthodes qui présentent toutes beaucoup d'inconvénients.Electrochemical sensors find an interesting application in the measurement of the concentration of dissolved oxygen in the treatment plant basins. In fact, the wastewater is treated with bacteria that are very sensitive to this dissolved oxygen concentration. The information provided by the sensors makes it possible to regulate a system of aeration of the basin so that the conditions are favorable to the bacteria. However, the sensors on the market do not give satisfactory results, in particular because of various contaminations and organic matter which is deposited on the electrode, thus modifying its sensitivity. With conventional sensors, it is generally used to combat contamination, mechanical methods such as forced air, pressurized water jet, abrasion; methods that all have a lot of disadvantages.

Afin d'éliminer la contamination de la surface du capteur, la demande déposée sous le numéro EP 04 405039.1 propose d'utiliser une électrode génératrice en diamant. Lorsqu'elle est mise sous tension, cette électrode génère des espèces fortement oxydantes, telles que des radicaux hydroxyles, capables de brûler efficacement des matières organiques.In order to eliminate contamination of the sensor surface, the application filed under the number EP 04 405039.1 proposes to use a diamond generator electrode. When energized, this electrode generates strongly oxidizing species, such as hydroxyl radicals, capable of efficiently burning organic material.

Cependant, l'effet obtenu par ces espèces oxydantes ne permet pas d'empêcher totalement toute contamination. Avec le temps, le capteur est progressivement affecté, ce qui détériore la précision de la mesure.However, the effect obtained by these oxidizing species does not completely prevent any contamination. Over time, the sensor is progressively affected, which deteriorates the accuracy of the measurement.

L'un des buts de la présente invention est donc de résoudre le problème susmentionné, en proposant un capteur dont la précision n'est pas tributaire des phénomènes de contamination.One of the aims of the present invention is therefore to solve the aforementioned problem by proposing a sensor whose accuracy is not dependent on the phenomena of contamination.

Divulgation de l'inventionDisclosure of the invention

De façon plus précise, l'invention concerne un procédé d'auto-nettoyage d'une électrode de travail d'un capteur électrochimique comportant, d'une part, une électrode de travail de type micro-disques et sa contre-électrode, et une électrode de référence reliées à un potentiostat, et, d'autre part, une électrode génératrice en diamant dopé au bore et sa contre-électrode reliées à une source de courant. L'ensemble de ces électrodes est, en outre, connecté à une électronique de contrôle et de mesure.More specifically, the invention relates to a method for self-cleaning a working electrode of an electrochemical sensor comprising, on the one hand, a working electrode of the micro-disk type and its counter-electrode, and a reference electrode connected to a potentiostat, and, secondly, a boron-doped diamond generating electrode and its counter-electrode connected to a current source. All of these electrodes are, in addition, connected to a control and measurement electronics.

Avantageusement, le procédé comprend les étapes suivantes :

  • application d'un courant anodique à l'électrode génératrice, et
  • application d'un courant cathodique à l'électrode génératrice.
Advantageously, the method comprises the following steps:
  • applying an anode current to the generator electrode, and
  • application of a cathode current to the generator electrode.

Le procédé d'auto-nettoyage peut précéder un procédé de mesure d'au moins une espèce dissoute dans un milieu aqueux. Dans ce cas, les électrodes de travail et de référence sont déconnectées de leur alimentation pendant l'étape d'auto-nettoyage.The self-cleaning process may precede a method of measuring at least one species dissolved in an aqueous medium. In this case, Working and reference electrodes are disconnected from their power supply during the self-cleaning step.

Brève description des dessinsBrief description of the drawings

D'autres détails de l'invention apparaîtront plus clairement à la lecture de la description qui suit, faite en référence au dessin annexé dans lequel :

  • les figures 2 et 3 sont, respectivement, des vues de dessus et en coupe d'un système d'électrodes selon l'invention,
  • les figures 4 et 5 illustrent la mise en ceuvre du système d'électrodes dans un dispositif de mesure selon l'invention, et
  • la figure 6 représente l'évolution de la concentration en oxygène dissous en fonction du temps lors de la production d'oxygène par l'électrode génératrice, pour différentes conditions hydrodynamiques.
Other details of the invention will emerge more clearly on reading the description which follows, made with reference to the appended drawing in which:
  • the Figures 2 and 3 are, respectively, top views and sectional views of an electrode system according to the invention,
  • the Figures 4 and 5 illustrate the implementation of the electrode system in a measuring device according to the invention, and
  • the figure 6 represents the evolution of the concentration of dissolved oxygen as a function of time during the oxygen production by the generating electrode, for different hydrodynamic conditions.

Mode(s) de réalisation de l'inventionMode (s) of realization of the invention

Dans la description ci-dessous, une tension négative se réfère à un potentiel cathodique et une tension positive se réfère à un potentiel anodique.In the description below, a negative voltage refers to a cathode potential and a positive voltage refers to an anode potential.

Les figures 2 et 3 représentent une puce 21. Elle possède un substrat électriquement conducteur 20 qui se présente sous la forme d'une plaque, par exemple carrée, typiquement, de 2 à 10 mm de côté et 0.5 mm d'épaisseur. Cette plaque est, avantageusement, réalisée en silicium rendu conducteur par dopage selon des techniques bien connues de l'homme du métier. Elle est posée sur un support 35, réalisé en polymère isolant.The Figures 2 and 3 represent a chip 21. It has an electrically conductive substrate 20 which is in the form of a plate, for example square, typically 2 to 10 mm side and 0.5 mm thick. This plate is advantageously made of silicon made conductive by doping according to techniques well known to those skilled in the art. It is placed on a support 35, made of insulating polymer.

Le substrat 20 est percé, sur sa face supérieure, d'un réseau régulier de cavités sensiblement cylindriques 22, d'axe perpendiculaire au plan du substrat. Typiquement, ces cavités ont un diamètre de 2 à 20 µm, une profondeur de 2 à 20 µm et sont espacées les unes des autres d'environ 40 à 400 µm.The substrate 20 is pierced on its upper face with a regular network of substantially cylindrical cavities 22, with an axis perpendicular to the plane of the substrate. Typically, these cavities have a diameter of 2 to 20 microns, a depth of 2 to 20 microns and are spaced from each other by about 40 to 400 microns.

Le fond de chaque cavité 22 est partiellement recouvert d'une métallisation 23 qui présente un diamètre inférieur de 0.5 à 5 µm à celui de la cavité 22. L'ensemble des métallisations 23 constitue l'électrode de travail du système. Avantageusement, un dépôt métallique peut être réalisé sur les métallisations 23 par croissance galvanique.The bottom of each cavity 22 is partially covered by a metallization 23 which has a diameter 0.5 to 5 μm smaller than that of the cavity 22. The set of metallizations 23 constitutes the working electrode of the system. Advantageously, a metal deposit can be made on the metallizations 23 by galvanic growth.

La face supérieure du substrat 20 est recouverte d'une couche isolante 25, dite de passivation, qui est formée, par exemple, d'un empilement de deux sous-couches de SiO2 et Si3N4 et a une épaisseur d'environ 0.1 à 1 µm. Cette couche est percée d'un réseau régulier d'ouvertures traversantes circulaires 27 centrées sur les cavités 22, de diamètre inférieur à celui des cavités.The upper face of the substrate 20 is covered with an insulating layer 25, called passivation, which is formed, for example, of a stack of two sublayers of SiO 2 and Si 3 N 4 and has a thickness of about 0.1 to 1 μm. This layer is pierced with a regular network of circular through openings 27 centered on the cavities 22, of smaller diameter than the cavities.

La structure qui vient d'être décrite est complétée par une électrode génératrice 30, qui peut être en diamant, disposée autour des électrodes de mesure selon l'enseignement du document WO 02/095387 et de la demande EP 04 405039.1 .The structure which has just been described is completed by a generating electrode 30, which may be made of diamond, arranged around the measurement electrodes according to the teaching of the document WO 02/095387 and demand EP 04 405039.1 .

Plus particulièrement, l'électrode 30 est formée d'une mince couche de diamant rendu conducteur par dopage, qui est percée d'ouvertures circulaires 26 de diamètre supérieur à celui des cavités 22 et disposée de manière à ce que chaque ouverture 26 soit concentrique à une micro-électrode. Avantageusement, le diamant utilisé pour former l'électrode est dopé au bore.More particularly, the electrode 30 is formed of a thin layer of diamond made conductive by doping, which is pierced with circular openings 26 of diameter greater than that of the cavities 22 and arranged so that each opening 26 is concentric to a micro-electrode. Advantageously, the diamond used to form the electrode is doped with boron.

En variante, les électrodes de travail et génératrice peuvent être réalisées selon la structure représentée sur la figure 1.In a variant, the working and generating electrodes may be made according to the structure represented on the figure 1 .

Lorsque l'électrode 30 est mise sous tension, elle permet de générer des espèces fortement oxydantes telles que des radicaux hydroxyles. Comme expliqué dans l'introduction, ceux-ci peuvent avoir une action néfaste sur des revêtements en polymère 34, par exemple en silicone, généralement déposés sur les contacts électriques de l'électrode génératrice, plus précisément à l'interface entre le revêtement 34 et la couche de diamant 30 au contact du milieu.When the electrode 30 is energized, it makes it possible to generate strongly oxidizing species such as hydroxyl radicals. As explained in the introduction, these may have a detrimental effect on polymer coatings 34, for example silicone, generally deposited on the electrical contacts of the generating electrode, more precisely at the interface between the coating 34 and the diamond layer 30 in contact with the medium.

Pour éviter ces effets, une couche de protection 31 est déposée sur l'électrode génératrice en diamant 30 préalablement au revêtement 34, de sorte qu'il n'existe plus d'interface directe entre le revêtement 34 et la couche de diamant 30. Cette couche de protection est réalisée en un matériau inorganique électriquement isolant, tel que du SiO2 ou du Si3N4, qui, de plus, présentent une excellente stabilité en milieu aqueux. La couche 31 a une épaisseur comprise entre 0.1 et 0.5 µm. Elle est déposée et conformée selon les techniques connues de l'homme du métier.To avoid these effects, a protective layer 31 is deposited on the diamond generating electrode 30 prior to the coating 34, so that there is no longer a direct interface between the coating 34 and the diamond layer 30. protective layer is made of a material inorganic electrically insulating, such as SiO 2 or Si 3 N 4 , which, moreover, have excellent stability in aqueous medium. The layer 31 has a thickness of between 0.1 and 0.5 μm. It is deposited and shaped according to the techniques known to those skilled in the art.

Avantageusement, la couche de protection 31 est située à la périphérie de l'électrode 30 et forme un cadre de manière à recouvrir les éléments à protéger. Elle comprend des ouvertures 32 nécessaires à la connexion électrique avec l'électrode génératrice 30. Pour améliorer le contact électrique avec l'électrode 30, un cadre de contact métallique, non représenté, peut être déposé, par évaporation, sur la couche de protection 31 qui est munie de plusieurs ouvertures 32. Le cadre de contact peut aussi être réalisé séparément et ensuite collé à l'électrode 30, au niveau des ouvertures 32, par une colle conductrice.Advantageously, the protective layer 31 is located at the periphery of the electrode 30 and forms a frame so as to cover the elements to be protected. It comprises openings 32 necessary for the electrical connection with the generating electrode 30. To improve the electrical contact with the electrode 30, a metal contact frame, not shown, can be deposited, by evaporation, on the protective layer 31 which is provided with several openings 32. The contact frame can also be made separately and then bonded to the electrode 30, at the openings 32, by a conductive adhesive.

Le revêtement en polymère 34 est ensuite déposé sur les contacts électriques et, s'il y en a un, sur le cadre de contact. Comme on peut le voir sur la figure 3, le revêtement déborde sur la couche de protection 31 et recouvre également les surfaces latérales de la puce 21.The polymer coating 34 is then deposited on the electrical contacts and, if there is one, on the contact frame. As can be seen on the figure 3 the coating overflows over the protective layer 31 and also covers the lateral surfaces of the chip 21.

La puce 21 décrite ci-dessus comprend donc une électrode de travail (ensemble des métallisations 23) et une électrode génératrice 30. Elle est intégrée dans une tête de mesure 38 représentée, en coupe, à la figure 4. La tête de mesure 38 comporte, en outre, une contre-électrode pour l'électrode de travail 40 et une électrode de référence 42. La tête 38 est réalisée en un matériau non-métallique, du type polymère non conducteur. La tête 38 peut également comporter une contre-électrode pour l'électrode génératrice, mais on comprendra ci-après pourquoi il n'en figure pas dans le mode de réalisation décrit.The chip 21 described above therefore comprises a working electrode (set of metallizations 23) and a generating electrode 30. It is integrated in a measuring head 38 shown, in section, at the figure 4 . The measuring head 38 further comprises a counter-electrode for the working electrode 40 and a reference electrode 42. The head 38 is made of a non-metallic material of the non-conductive polymer type. The head 38 may also include a counter-electrode for the generating electrode, but it will be understood hereinafter why it does not appear in the embodiment described.

Les zones des électrodes destinées à être en contact avec le milieu à analyser affleurent à la surface de la tête de mesure 38 et sont situées à faible distance les unes des autres. Des éléments de connectique 44 traversent la tête de mesure pour relier les électrodes à l'électronique 46 de contrôle, de mesure et d'interface avec l'extérieur (affichage, enregistrement, etc.).The areas of the electrodes intended to be in contact with the medium to be analyzed are flush with the surface of the measuring head 38 and are located at a short distance from one another. Connector elements 44 pass through the measuring head to connect the electrodes to the electronics 46 control, measurement and interface with the outside (display, recording, etc.).

En résumé, on retiendra que l'électrode génératrice et sa contre-électrode sont branchées à une source de courant, tandis que l'électrode de travail et sa contre-électrode, d'une part, et l'électrode de référence, d'autre part, sont branchées à un potentiostat qui permet d'imposer une tension entre les électrodes et, ainsi, de mesurer, à une tension déterminée, le courant circulant entre l'électrode de travail et sa contre-électrode.In summary, it will be remembered that the generator electrode and its counter-electrode are connected to a current source, while the working electrode and its counterelectrode, on the one hand, and the reference electrode, on the other hand, are connected to a potentiostat which makes it possible to impose a voltage between the electrodes and thus to measure, at a determined voltage, the current flowing between the working electrode and its counter-electrode.

La contre-électrode de l'électrode de travail 40 est avantageusement réalisée en un matériau conducteur et chimiquement stable, tel que de l'acier inox, de l'or ou du platine. Sa surface est typiquement 100 fois supérieure à celle des micro-disques de l'électrode de travail 23. L'électrode de référence 42 est choisie en fonction de l'application visée. Pour une mesure de la concentration d'oxygène dans un milieu aqueux, une électrode du type Ag/AgCl est généralement préférée.The counter-electrode of the working electrode 40 is advantageously made of a conductive and chemically stable material, such as stainless steel, gold or platinum. Its surface is typically 100 times greater than that of the micro-disks of the working electrode 23. The reference electrode 42 is chosen according to the intended application. For a measurement of the oxygen concentration in an aqueous medium, an Ag / AgCl electrode is generally preferred.

Comme indiqué ci-dessus pour la puce 21, une couche en matériau polymère 34 est déposée sur les bords des substrats des électrodes.As indicated above for the chip 21, a layer of polymer material 34 is deposited on the edges of the electrode substrates.

La tête de mesure 38 est montée de manière étanche à l'extrémité d'un corps de sonde 48, généralement de forme tubulaire, visible sur la figure 5. Pour assurer que les éléments de connectique 44 de la tête 38 sont positionnés correctement par rapport à l'électronique 46 qui prend place dans le corps de sonde, la tête 38 est dotée de trous de positionnement 50 qui coopèrent avec des ergots disposés dans le corps 48. Il est ainsi très facile, en cas de besoin, de remplacer la tête de mesure 38. La tête de mesure est ensuite fixée au corps de la sonde à l'aide d'une bague 49, qui est vissée sur le corps de la sonde de manière à assurer l'étanchéité de l'ensemble.The measuring head 38 is sealingly mounted at the end of a probe body 48, generally tubular in shape, visible on the figure 5 . To ensure that the connector elements 44 of the head 38 are positioned correctly relative to the electronics 46 which takes place in the probe body, the head 38 is provided with positioning holes 50 which cooperate with lugs arranged in the body 48. It is thus very easy, in case of need, to replace the measuring head 38. The measurement head is then fixed to the body of the probe by means of a ring 49, which is screwed on the body of the probe. the probe so as to seal the assembly.

Dans une variante avantageuse illustrée, le corps de sonde 48 est réalisé en un matériau métallique, tel que de l'acier inox, et sert de contre-électrode pour l'électrode génératrice. Eventuellement, le corps 48 sert de contre-électrode pour l'électrode génératrice et/ou pour l'électrode de travail. Le corps 48 peut également comporter une partie non-métallique et une partie métallique, cette dernière étant utilisée comme contre-électrode.In an advantageous variant illustrated, the probe body 48 is made of a metallic material, such as stainless steel, and serves as a counter electrode for the generator electrode. Optionally, the body 48 serves as a counter electrode for the generator electrode and / or the working electrode. The body 48 may also comprise a non-metallic part and a metal part, the latter being used as a counter-electrode.

L'extrémité du corps de sonde 48 qui reçoit la tête de mesure 38 est inclinée d'un angle compris entre 0 et 90°, préférablement compris entre 30 et 60°, préférablement de l'ordre de 45°, par rapport au reste du corps 48. Ce dernier étant plongé verticalement dans le liquide à analyser, l'angle que présente son extrémité permet d'améliorer les conditions hydrodynamiques autour de la tête de mesure 38, particulièrement lorsque le milieu est agité.The end of the probe body 48 which receives the measuring head 38 is inclined at an angle between 0 and 90 °, preferably between 30 and 60 °, preferably of the order of 45 °, relative to the rest of the 48. The latter being immersed vertically in the liquid to be analyzed, the angle that has its end improves the hydrodynamic conditions around the measuring head 38, particularly when the medium is agitated.

Un procédé d'utilisation du capteur électrochimique qui vient d'être décrit est expliqué ci-après, particulièrement en référence à une application à la mesure d'oxygène dissous dans un milieu aqueux.A method of using the electrochemical sensor which has just been described is explained below, particularly with reference to an application to the measurement of dissolved oxygen in an aqueous medium.

La mesure ampérométrique de la concentration en oxygène dissous dans un milieu aqueux est réalisée en appliquant un potentiel de réduction adéquat entre l'électrode de travail et l'électrode de référence. Il se créé alors un courant de réduction proportionnel à la concentration d'oxygène dissous dans le liquide circulant entre l'électrode de travail et sa contre-électrode. On peut alors mesurer le courant dans l'électrode de travail, ce courant étant représentatif de la concentration en oxygène du milieu.The amperometric measurement of the dissolved oxygen concentration in an aqueous medium is performed by applying an adequate reduction potential between the working electrode and the reference electrode. A reduction current is then created proportional to the concentration of dissolved oxygen in the liquid circulating between the working electrode and its counter-electrode. The current can then be measured in the working electrode, this current being representative of the oxygen concentration of the medium.

Une procédure d'auto-calibration, (non revendiquée) dont un exemple sera donné ci-dessous, permet de compenser efficacement les dérives dues à des pertes de sensibilité de l'électrode de travail. Cette procédure in situ est basée sur un changement de la concentration locale en oxygène dissous, obtenu au moyen de variations adaptées de la polarisation de l'électrode génératrice qui entraînent l'électrolyse de l'eau selon la réaction :

        2H2O → O2 + 4H+ + 4e-

A self-calibration procedure (not claimed), an example of which will be given below, makes it possible to effectively compensate the drifts due to loss of sensitivity of the working electrode. This in situ procedure is based on a change in the local concentration of dissolved oxygen, obtained by means of variations of the polarization of the generating electrode which lead to the electrolysis of the water according to the reaction:

2H 2 O → O 2 + 4H + + 4th -

Cette réaction modifie localement la concentration en oxygène dissous de manière précise et indépendante de la teneur en oxygène du milieu environnant. En effet, la densité et la durée d'application du courant reçu par l'électrode génératrice permettent de contrôler la production d'oxygène.This reaction locally changes the concentration of dissolved oxygen precisely and independently of the oxygen content of the surrounding environment. Indeed, the density and duration of application of the current received by the generating electrode can control the production of oxygen.

La différence entre la réponse de l'électrode de travail avant et après la production d'oxygène par l'électrode génératrice permet de déduire un facteur de calibration. Ce dernier représente la sensibilité du capteur et fournit, pour un capteur donné, un coefficient de proportionnalité entre la concentration en oxygène du milieu à analyser et le courant effectivement mesuré entre l'électrode de travail et sa contre-électrode.The difference between the response of the working electrode before and after the oxygen production by the generating electrode makes it possible to deduce a calibration factor. The latter represents the sensitivity of the sensor and provides, for a given sensor, a coefficient of proportionality between the oxygen concentration of the medium to be analyzed and the actual current measured between the working electrode and its counter-electrode.

De manière générale, le temps pendant lequel la concentration en oxygène dissous est localement augmentée dépend des conditions d'agitation du milieu.In general, the time during which the dissolved oxygen concentration is locally increased depends on the stirring conditions of the medium.

Comme le montre la figure 6, qui représente, sur les courbes a à d, l'évolution de la concentration d'oxygène en fonction du temps dans différentes conditions d'agitation, il a été constaté de manière surprenante que, pour une puce 21 dotée de micro-disques, la concentration croît de manière linéaire pendant les premiers instants de production d'oxygène, sans que les conditions hydrodynamiques n'aient d'influence. Cette phase linéaire dure environ 500 ms. Ainsi, si l'on n'applique le courant d'électrolyse à l'électrode génératrice que pendant une durée réduite, l'agitation du milieu ne perturbe pas la concentration en oxygène dans la zone de diffusion et il est alors possible de mesurer précisément le courant engendré par l'oxygène effectivement produit par l'électrode génératrice et de calculer un facteur de cal ibration.As shown in figure 6 , which represents, on the curves a to d, the evolution of the concentration of oxygen as a function of time under different stirring conditions, it has surprisingly been found that, for a chip 21 equipped with micro-disks, the concentration increases linearly during the first instants of oxygen production, without the hydrodynamic conditions having any influence. This linear phase lasts about 500 ms. Thus, if the electrolysis current is applied to the generator electrode only during a reduced duration, stirring of the medium does not disturb the oxygen concentration in the diffusion zone and it is then possible to measure precisely the current generated by the oxygen actually produced by the generating electrode and calculating a caliper factor.

Dans un milieu de faible conductivité, le champ électrique engendré par l'électrode génératrice peut perturber le comportement de l'électrode de référence au cours de l'auto-calibration si, lors de cette procédure, la mesure se fait simultanément avec le fonctionnement de l'électrode génératrice. Pour pallier cet inconvénient, le mesure d'auto-calibration est réalisée juste après l'arrêt de l'alimentation de l'électrode génératrice, sur un point ou en moyennant les valeurs obtenue sur une certaine plage, comme on le verra ci-dessous. Toutefois, une mesure peut être effectuée pendant l'application d'un courant à l'électrode génératrice.In a medium of low conductivity, the electric field generated by the generating electrode can disturb the behavior of the reference electrode during the self-calibration if, during this procedure, the measurement is done simultaneously with the operation of the generator electrode. To overcome this drawback, the self-calibration measurement is performed just after stopping the supply of the generator electrode, on a point or by averaging the values obtained over a certain range, as will be seen below. . However, a measurement can be made during the application of a current to the generator electrode.

Bien qu'une procédure d'auto-calibration permette de compenser les éventuelles dérives dues à l'encrassement des micro-électrodes, il est néanmoins intéressant de pouvoir conserver une bonne sensibilité de l'électrode de travail. Ceci est obtenu par une opération d'auto-nettoyage, réalisée in situ, et rendue possible grâce aux propriétés du diamant dopé au bore de l'électrode génératrice. Cette opération peut également être réalisée à titre préventif.Although a self-calibration procedure makes it possible to compensate for any drifts due to fouling of the micro-electrodes, it is nevertheless advantageous to be able to maintain a good sensitivity of the working electrode. This is achieved by a self-cleaning operation, performed in situ, and made possible by the properties of the diamond doped with boron of the generator electrode. This operation can also be carried out as a preventive measure.

L'auto-nettoyage est obtenu par la conjonction de plusieurs effets causés par l'application à l'électrode de diamant de courants de polarité et de densité différentes. Tout d'abord, un courant anodique entraîne une production d'ion H+, ce qui acidifie le milieu aqueux proche de l'électrode. Ainsi, les dépôts de type tartre (carbonate de calcium, oxydes de magnésium) sont dissous. En outre, ce type de courant appliqué sur une électrode de diamant dopé au bore entraîne une production d'espèces fortement actives, telles que des radicaux hydroxyles, qui dégradent les dépôts organiques comme les bio-films, et possèdent une activité biocide.Self-cleaning is achieved by the conjunction of several effects caused by the application to the diamond electrode of currents of different polarity and density. Firstly, an anode current causes H + ion production, which acidifies the aqueous medium close to the electrode. Thus scale deposits (calcium carbonate, magnesium oxides) are dissolved. In addition, this type of current applied to a boron-doped diamond electrode results in the production of highly active species, such as hydroxyl radicals, which degrade organic deposits such as bio-films, and possess a biocidal activity.

De plus, l'application d'un courant cathodique entraîne la production d'ions OH-, ce qui rend basique le milieu aqueux proche de l'électrode. Ainsi, une alternance de courants anodique/cathodique fait fortement varier le pH à proximité de l'électrode de diamant, empêchant ainsi la formation d'un bio-film.In addition, the application of a cathode current results in the production of OH - ions, which makes basic the aqueous medium close to the electrode. Thus, an alternation of anodic / cathodic currents causes the pH to vary greatly in the vicinity of the diamond electrode, thus preventing the formation of a bio-film.

L'étape d'auto-nettoyage est appliquée à intervalles définis, de manière à ce que l'oxygène produit lors de l'application d'un courant anodique ne perturbe pas les mesures ultérieures.The self-cleaning step is applied at defined intervals, so that the oxygen produced during the application of an anode current does not disturb the subsequent measurements.

Différentes procédures sont définies, comprenant chacune une suite détaillée de séquences faites dans un ordre déterminé de manière à réaliser les étapes d'auto-nettoyage, d'auto-calibration (non revendiquée) et de mesure (non revendiquée).Different procedures are defined, each comprising a detailed sequence of sequences made in a determined order so as to perform the steps of self-cleaning, self-calibration (unclaimed) and measurement (unclaimed).

L'électronique de contrôle 46 mentionnée ci-dessus comprend, en outre, un microprocesseur programmé pour gérer :

  • la durée des différentes étapes,
  • les différences de potentiel entre l'électrode de travail et de référence,
  • mesurer, sous une différence de potentiel déterminée et imposée par le potentiostat, le courant qui passe entre l'électrode de travail et sa contre-électrode,
  • le courant appliqué entre l'électrode génératrice et sa contre-électrode, et
  • la déconnexion des électrodes de travail et de référence au cours de la production d'oxygène de la phase d'auto-nettoyage.
The control electronics 46 mentioned above also comprises a microprocessor programmed to manage:
  • the duration of the different stages,
  • the potential differences between the working and reference electrode,
  • measuring, under a determined potential difference and imposed by the potentiostat, the current flowing between the working electrode and its counterelectrode,
  • the current applied between the generator electrode and its counter-electrode, and
  • the disconnection of the working and reference electrodes during oxygen production from the self-cleaning phase.

Les autres éléments de l'électronique de contrôle 46 sont parfaitement accessibles à l'homme du métier et ne sont donc pas décrits ici en détail.The other elements of the control electronics 46 are perfectly accessible to those skilled in the art and are therefore not described here in detail.

A intervalles définis, le courant circulant entre l'électrode de travail et sa contre-électrode est mesuré et la concentration en oxygène dissous est calculée au moyen du facteur de calibration déterminé préalablement. A titre d'exemple, une procédure type de mesure (non revendiquée), comprenant à titre facultatif une étape d'auto-nettoyage doux, comporte les séquences suivantes.

  • Attente et auto-nettoyage doux :
    1. i. Les électrodes de travail et de référence sont déconnectées de leur alimentation, pendant une durée typiquement comprise entre 0 et 60s, plus particulièrement de 15s.
    2. ii. Un auto-nettoyage doux est obtenu en appliquant un courant anodique de densité typiquement comprise entre 0.5 et 2 mA/cm2, plus particulièrement de 1 mA/cm2, pendant une période variant de 0.5 à 5s, typiquement 1 s, débutant immédiatement après la déconnexion mentionnée au point i. La durée restant pour cette étape permet à l'oxygène produit au niveau de l'électrode génératrice de se disperser par diffusion dans le milieu.
  • Activation de l'électrode de travail :
    1. i. Une activation anodique est obtenue en appliquant une tension typiquement comprise entre 200 et 1500mV, plus particulièrement de 500mV pendant une durée typiquement comprise entre 0.1 et 30s, plus particulièrement de 3s.
    2. ii. Une activation cathodique est obtenue en appliquant une tension typiquement comprise entre -200 et -1500mV, plus particulièrement de -1100mV pendant une durée typiquement comprise entre 0.1 et 10s, plus particulièrement de 1s.
  • Mesure et calcul
    1. i. Une stabilisation est obtenue en appliquant à l'électrode de travail une tension typiquement comprise entre -500 et - 1200mV, plus particulièrement de -900mV pendant une durée typiquement comprise entre 0.1 et 60s, plus particulièrement de 8s.
    2. ii. Une mesure et une détermination du courant moyen circulant entre l'électrode de travail et sa contre-électrode sont réalisées sous une tension typiquement comprise entre -500 et -1300mV, plus particulièrement de -900mV, pendant une durée typiquement comprise entre 0.1 et 30s, plus particulièrement de 2s.
    3. iii. La concentration en oxygène dissous est calculée à partir du courant déterminé à l'étape précédente et au moyen du facteur de calibration prédéterminé selon la procédure donnée ci-dessous.
At defined intervals, the current flowing between the working electrode and its counter-electrode is measured and the dissolved oxygen concentration is calculated using the previously determined calibration factor. By way of example, a typical measurement procedure (not claimed), optionally including a soft self-cleaning step, includes the following sequences.
  • Waiting and self-cleaning soft:
    1. i. The working and reference electrodes are disconnected from their power supply for a period of typically between 0 and 60 seconds, more particularly 15 seconds.
    2. ii. A mild self-cleaning is obtained by applying an anodic current density typically between 0.5 and 2 mA / cm 2 , more particularly 1 mA / cm 2 , for a period ranging from 0.5 to 5s, typically 1 s, starting immediately after the disconnection mentioned in point i. The remaining time for this step allows the oxygen produced at the generating electrode to disperse by diffusion in the medium.
  • Activation of the working electrode:
    1. i. Anodic activation is obtained by applying a voltage typically between 200 and 1500mV, more particularly 500mV for a duration typically between 0.1 and 30s, more particularly 3s.
    2. ii. Cathodic activation is obtained by applying a voltage typically between -200 and -1500mV, more particularly -1100mV for a duration typically between 0.1 and 10s, more particularly 1s.
  • Measurement and calculation
    1. i. A stabilization is obtained by applying to the working electrode a voltage typically between -500 and-1200mV, more particularly -900mV for a period typically between 0.1 and 60s, more particularly 8s.
    2. ii. A measurement and a determination of the average current flowing between the working electrode and its counterelectrode are carried out at a voltage typically between -500 and -1300mV, more particularly -900mV, for a duration typically between 0.1 and 30s, more particularly 2s.
    3. iii. The dissolved oxygen concentration is calculated from the current determined in the previous step and by means of the predetermined calibration factor according to the procedure given below.

Une telle procédure de mesure est répétée à une fréquence typiquement de 0.5 à 5 fois par minute selon les valeurs des paramètres définis ci-dessus, plus particulièrement de 2 mesures par minutes.Such a measurement procedure is repeated at a frequency typically of 0.5 to 5 times per minute according to the values of the parameters defined above, more particularly of 2 measurements per minute.

Une procédure d'auto-calibration (non revendiquée) comprend, typiquement, les étapes suivantes :

  • Attente :
    1. i. Les électrodes de travail et de référence sont déconnectées de leur alimentation, pendant une durée typiquement comprise entre 0 et 60s, plus particulièrement de 15s.
  • Activation de l'électrode de travail :
    1. i. Une activation anodique est obtenue en appliquant une tension typiquement comprise entre 200 et 1500mV, plus particulièrement de 500mV pendant une durée typiquement comprise entre 0.1 et 30s, plus particulièrement de 3s.
    2. ii. Une activation cathodique est obtenue en appliquant une tension typiquement comprise entre -200 et -1500mV, plus particulièrement de -1100mV pendant une durée typiquement comprise entre 0.1 et 10s, plus particulièrement de 1 s.
  • Mesure de la concentration en oxygène avant l'application d'un courant à l'électrode génératrice :
    1. i. Une stabilisation est obtenue en appliquant à l'électrode de travail une tension typiquement comprise entre -500 et - 1300mV, plus particulièrement de -900mV pendant une durée typiquement comprise entre 0.1 et 60s, plus particulièrement de 8s.
    2. ii. Une mesure et une détermination du courant moyen circulant entre l'électrode de travail et sa contre-électrode sont réalisées sous une tension typiquement comprise entre -500 et -1300mV, plus particulièrement de -900mV, pendant une durée typiquement comprise entre 0.1 et 30s, plus particulièrement de 2s.
  • Application d'un courant d'auto-calibration à l'électrode génératrice de manière à produire une augmentation définie de la concentration locale en oxygène dissous:
    1. i. Un courant anodique d'une densité typiquement comprise entre 0.1 et 10 mA/cm2, plus particulièrement de 1 mA/cm2 est appliqué pendant une durée typiquement comprise entre 0.1 et 1 s plus particulièrement de 0.4s.
  • Mesure de la concentration en oxygène après l'application d'un courant à l'électrode génératrice :
    1. i. Une stabilisation est obtenue en appliquant à l'électrode de travail une tension typiquement comprise entre -500 et - 1300mV, plus particulièrement de -900mV pendant une durée typiquement comprise entre 0.01 et 0.1 s, plus particulièrement de 0.04s.
    2. ii. Une mesure et une détermination du courant moyen circulant entre l'électrode de travail et sa contre-électrode sont réalisées sous une tension typiquement comprise entre -500 et -1300mV, plus particulièrement de -900mV, pendant une durée typiquement comprise entre 0.01 et 0.2s, plus particulièrement de 0.08s.
    3. iii. Un nouveau facteur de calibration de l'électrode de travail est calculé à partir de la différence des mesures avant et après application du courant d'auto-calibration sur l'électrode auxiliaire
A self-calibration procedure (not claimed) typically includes the following steps:
  • Waiting:
    1. i. The working and reference electrodes are disconnected from their power supply for a period of typically between 0 and 60 seconds, more particularly 15 seconds.
  • Activation of the working electrode:
    1. i. Anodic activation is obtained by applying a voltage typically between 200 and 1500mV, more particularly 500mV for a duration typically between 0.1 and 30s, more particularly 3s.
    2. ii. Cathodic activation is obtained by applying a voltage typically between -200 and -1500mV, more particularly -1100mV for a period typically between 0.1 and 10s, more particularly 1 s.
  • Measuring the oxygen concentration before applying a current to the generator electrode:
    1. i. A stabilization is obtained by applying to the working electrode a voltage typically between -500 and-1300mV, more particularly -900mV for a period typically between 0.1 and 60s, more particularly 8s.
    2. ii. A measurement and a determination of the average current flowing between the working electrode and its counterelectrode are carried out at a voltage typically between -500 and -1300mV, more particularly -900mV, for a duration typically between 0.1 and 30s, more particularly 2s.
  • Applying a self-calibration current to the generator electrode so as to produce a defined increase in the local dissolved oxygen concentration:
    1. i. An anode current of a density typically between 0.1 and 10 mA / cm 2 , more particularly 1 mA / cm 2 is applied for a duration typically between 0.1 and 1 s, more particularly 0.4 s.
  • Measuring the oxygen concentration after applying a current to the generator electrode:
    1. i. Stabilization is obtained by applying to the working electrode a voltage typically between -500 and -1300mV, more particularly -900mV for a duration typically between 0.01 and 0.1 s, more particularly 0.04s.
    2. ii. A measurement and a determination of the average current flowing between the working electrode and its counter-electrode are made at a voltage typically between -500 and -1300mV, more particularly -900mV, during a typically between 0.01 and 0.2s, more particularly 0.08s.
    3. iii. A new calibration factor of the working electrode is calculated from the difference of measurements before and after application of the auto-calibration current on the auxiliary electrode

Une telle procédure d'auto-calibration est répétée à une fréquence de 0.1 à 48 fois par jour, typiquement de 1 fois par jour.Such a self-calibration procedure is repeated at a frequency of 0.1 to 48 times per day, typically 1 time per day.

Une procédure d'auto-nettoyage comprend, typiquement, les étapes suivantes :

  1. i. application d'un courant anodique à l'électrode génératrice d'une densité typiquement comprise entre 0.5 et 100 mA/cm2, plus particulièrement de 2 mA/cm2 pendant une durée typiquement comprise entre 0.5 et 60s, plus particulièrement de 3s,
  2. ii. application d'un courant cathodique à l'électrode génératrice d'une densité typiquement comprise entre 0.5 et 100 mA/cm2, plus particulièrement de 2 mA/cm2 pendant une durée typiquement comprise entre 0.5 et 60s, plus particulièrement de 3s, et
  3. iii. répétition des deux étapes précédentes de 1 à 30 fois, plus particulièrement de 3 fois.
A self-cleaning procedure typically includes the following steps:
  1. i. applying an anode current to the generating electrode with a density typically between 0.5 and 100 mA / cm 2 , more particularly 2 mA / cm 2 for a duration typically between 0.5 and 60 s, more particularly 3 s,
  2. ii. applying a cathode current to the generating electrode with a density typically between 0.5 and 100 mA / cm 2 , more particularly 2 mA / cm 2 for a duration typically between 0.5 and 60 s, more particularly 3 s, and
  3. iii. repetition of the two preceding steps from 1 to 30 times, more particularly 3 times.

Une telle procédure d'auto-nettoyage est répétée à une fréquence de 10 à 200 fois par jour, typiquement de 100 fois par jour.Such a self-cleaning procedure is repeated at a frequency of 10 to 200 times a day, typically 100 times a day.

Ainsi sont proposées différentes procédures in situ particulièrement avantageuses d'auto-calibration (non revendiquée), d'auto-nettoyage et de mesure (non revendiquée) qui permettent de conserver une bonne précision d'un capteur électrochimique en évitant l'influence de toute contamination due au milieu de mesure. Par ailleurs, un capteur électrochimique peut permettre un auto-nettoyage, en évitant que les espèces oxydantes ne s'attaquent aux éléments constitutifs du capteur.Thus are proposed various particularly advantageous in-situ procedures of auto-calibration (not claimed), self-cleaning and measurement (not claimed) which make it possible to maintain a good accuracy of an electrochemical sensor while avoiding the influence of any contamination due to the measuring medium. Moreover, an electrochemical sensor can allow self-cleaning, by preventing the oxidizing species from attacking the constituent elements of the sensor.

La présente invention ne se limite pas à un capteur électrochimique mesurant la concentration en oxygène dissous dans un milieu. En effet, il est possible d'établir une corrélation entre les courants mesurés pour différentes espèces analysées autre que l'oxygène, par exemple, du chlore ou de l'ozone.The present invention is not limited to an electrochemical sensor measuring the concentration of dissolved oxygen in a medium. Indeed, it is possible to correlate the currents measured for different species analyzed other than oxygen, for example, chlorine or ozone.

Claims (7)

  1. A self-cleaning method for a working electrode of an electrochemical sensor including a working electrode of the micro-disc type (23) and its counter electrode (40) and a reference electrode (42) connected to a potentiostat, on the one hand, and a generating electrode (30) in diamond doped with boron and its counter electrode (48) connected to a current source on the other hand, the set of these electrodes being further connected to an electronic control and measuring unit (46), said method comprising the following steps:
    - applying an anode current to the generating electrode, and
    - applying a cathode current to the generating electrode.
  2. The self cleaning method according to claim 1, characterized in that said anode and cathode currents are applied with a density between 0.5 and 100 mA/cm2, more particularly 2 mA/cm2, for a time between 0.5 and 60 s, more particularly 3 s.
  3. The self-cleaning method according to any of claims 1 and 2, characterized in that the steps for applying an anode current and a cathode current are repeated from 1 to 30 times, more particularly 3 times.
  4. The self-cleaning method according to any of claims 1 to 3, characterized that said sensor is intended to measure the concentration of dissolved oxygen in an aqueous medium.
  5. The self-cleaning method according to any of claims 1 to 4, intended to precede a step for measuring at least one dissolved species in an aqueous medium with a sensor as defined in claim 1, characterized in that the working and reference electrodes are disconnected from their power supply during the self-cleaning step.
  6. The self-cleaning method according to claim 5, characterized in that:
    - the working and reference electrodes are disconnected from their power supply, for a time between 0 and 60 s, more particularly 15 s,
    - self-cleaning is obtained by applying an anode current with a density between 0.5 and 2 mA/cm2, more particularly 1 mA/cm2, for a period ranging from 0.5 to 5 s, more particularly 1 s, starting immediately after said disconnection.
  7. The self-cleaning method according to any of claims 5 and 6, characterized in that said dissolved species is oxygen.
EP06743351A 2005-04-22 2006-04-19 Method using an electrochemical sensor and electrodes forming said sensor Not-in-force EP1872116B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP06743351A EP1872116B1 (en) 2005-04-22 2006-04-19 Method using an electrochemical sensor and electrodes forming said sensor

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP05103304A EP1715334A1 (en) 2005-04-22 2005-04-22 Procedure utilising an electrochemical sensor and electrodes forming the sensor
PCT/EP2006/061681 WO2006111550A2 (en) 2005-04-22 2006-04-19 Method using an electrochemical sensor and electrodes forming said sensor
EP06743351A EP1872116B1 (en) 2005-04-22 2006-04-19 Method using an electrochemical sensor and electrodes forming said sensor

Publications (2)

Publication Number Publication Date
EP1872116A2 EP1872116A2 (en) 2008-01-02
EP1872116B1 true EP1872116B1 (en) 2011-10-12

Family

ID=34939469

Family Applications (2)

Application Number Title Priority Date Filing Date
EP05103304A Withdrawn EP1715334A1 (en) 2005-04-22 2005-04-22 Procedure utilising an electrochemical sensor and electrodes forming the sensor
EP06743351A Not-in-force EP1872116B1 (en) 2005-04-22 2006-04-19 Method using an electrochemical sensor and electrodes forming said sensor

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP05103304A Withdrawn EP1715334A1 (en) 2005-04-22 2005-04-22 Procedure utilising an electrochemical sensor and electrodes forming the sensor

Country Status (6)

Country Link
US (1) US7875164B2 (en)
EP (2) EP1715334A1 (en)
KR (1) KR20080002964A (en)
CN (1) CN101163966B (en)
AT (1) ATE528641T1 (en)
WO (1) WO2006111550A2 (en)

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2241882A1 (en) * 2009-04-15 2010-10-20 Neroxis SA Amperometric electrochemical sensor and manufacturing method
US9322801B2 (en) * 2009-05-14 2016-04-26 Honeywell International Inc. Apparatus and method of regenerating electrochemical gas sensors
GB201216859D0 (en) * 2012-09-20 2012-11-07 Univ Southampton Apparatus for sensing at least one parameter in water
GB201216867D0 (en) * 2012-09-20 2012-11-07 Univ Southampton Apparatus for sensing at least one parameter in water
GB201603680D0 (en) 2016-03-03 2016-04-20 Ucl Business Plc Device
TWI718284B (en) 2016-04-07 2021-02-11 美商零質量純水股份有限公司 Solar thermal unit
US10357739B2 (en) 2016-05-20 2019-07-23 Zero Mass Water Inc. Systems and methods for water extraction control
EP3507597B1 (en) 2016-08-31 2024-05-08 Honeywell International Inc. System and method for identifying and cleaning contamination of an electrochemical sensor
AU2018300250B2 (en) 2017-07-14 2024-04-18 Source Global, PBC Systems for controlled treatment of water with ozone and related methods therefor
US11359356B2 (en) 2017-09-05 2022-06-14 Source Global, PBC Systems and methods for managing production and distribution of liquid water extracted from air
AU2018329660B2 (en) 2017-09-05 2023-11-09 Source Global, PBC Systems and methods to produce liquid water extracted from air
MX2020004213A (en) 2017-10-06 2021-01-15 Zero Mass Water Inc Systems for generating water with waste heat and related methods therefor.
AU2018380168B2 (en) 2017-12-06 2023-11-02 Source Global, PBC Systems for constructing hierarchical training data sets for use with machine-learning and related methods therefor
WO2019161339A1 (en) 2018-02-18 2019-08-22 Zero Mass Water, Inc. Systems for generating water for a container farm and related methods therefor
AU2019265024B2 (en) 2018-05-11 2024-09-26 Source Global, PBC Systems for generating water using exogenously generated heat, exogenously generated electricity, and exhaust process fluids and related methods therefor
BR112021007178A2 (en) 2018-10-19 2021-07-20 Source Global, PBC systems and methods to generate liquid water using highly efficient techniques that optimize production
US20200124566A1 (en) 2018-10-22 2020-04-23 Zero Mass Water, Inc. Systems and methods for detecting and measuring oxidizing compounds in test fluids
CN113747962A (en) 2019-04-22 2021-12-03 环球源公司 Water vapor adsorption air drying system and method for producing liquid water from air
TW202202840A (en) * 2020-02-21 2022-01-16 美商半導體組件工業公司 Potentiostat with offset calibration
US12007358B2 (en) * 2020-02-21 2024-06-11 Semiconductor Components Industries, Llc Potentiostat with offset calibration
US11814820B2 (en) 2021-01-19 2023-11-14 Source Global, PBC Systems and methods for generating water from air

Family Cites Families (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4457808A (en) * 1983-05-16 1984-07-03 General Signal Corporation Method and means for recalibrating electrochemical cells in situ
US4762594A (en) * 1987-01-29 1988-08-09 Medtest Systems, Inc. Apparatus and methods for sensing fluid components
US5098547A (en) * 1988-10-11 1992-03-24 Bryan Avron I Dissolved oxygen sensor calibration, monitoring and reporting system
US5001124A (en) 1990-02-02 1991-03-19 Syntex (U.S.A.) Inc. 4-isoxazolecarboxamide derivatives
US5230785A (en) * 1991-05-31 1993-07-27 Poolchem, Inc. Method and apparatus for analysis of swimming pool water and analytical cell utilized therein
DE69306542T2 (en) * 1993-01-08 1997-05-15 Nippon Electric Co Method and device for wet treatment of solid surfaces
GB9412820D0 (en) * 1994-06-25 1994-08-17 Siemens Plessey Controls Ltd Water quality measuring apparatus
GB9413525D0 (en) * 1994-07-05 1994-08-24 Unilever Plc Improvements in or relating to electrochemical instruments
RO117948B1 (en) * 1995-12-19 2002-09-30 Institutul De Cercetare Şi Proiectare Pentru Electrotehnică Electrochemical probe with zirconia-type ceramic electrolyte for oxygen analyzer
GB9609301D0 (en) * 1996-05-03 1996-07-10 Wallace & Tiernan Ltd Measuring chlorine concentration
DE19621997C1 (en) * 1996-05-31 1997-07-31 Siemens Ag Electrochemical sensor e.g. for gas determination
FR2779523B1 (en) * 1998-06-09 2000-08-11 Grp Pour L Evaluation Des Mesu MULTI-PARAMETER SENSOR FOR METAL DETECTION, PARTICULARLY IN RELEASE WATER OR IN FILTERED WATER, IN A SANITATION SYSTEM, AND METHOD USING THE SAME
JP2000093907A (en) * 1998-09-21 2000-04-04 Dainippon Screen Mfg Co Ltd Cleaning apparatus using electrolytic ion water
US6402689B1 (en) * 1998-09-30 2002-06-11 Sicel Technologies, Inc. Methods, systems, and associated implantable devices for dynamic monitoring of physiological and biological properties of tumors
RU2207558C2 (en) * 1999-01-29 2003-06-27 Государственное унитарное предприятие "Уральский научно-исследовательский химический институт с опытным заводом" Procedure to clean measurement electrode
US20010001441A1 (en) * 2000-06-19 2001-05-24 Zdunek Alan D. Method and apparatus for measuring coating quality
CH697478B1 (en) * 2001-05-22 2008-11-14 Adamant Technologies Sa electrode for electrochemical sensor system and method for determining the pH of a chlorinated water.
US7201831B2 (en) * 2002-02-22 2007-04-10 Water Security And Technology, Inc. Impurity detection device
US20040132825A1 (en) * 2002-03-04 2004-07-08 Bacopoulos Nicholas G. Methods of treating cancer with HDAC inhibitors
US7456219B2 (en) * 2002-03-04 2008-11-25 Merck Hdac Research, Llc Polymorphs of suberoylanilide hydroxamic acid
EP2322160A1 (en) * 2002-03-04 2011-05-18 Merck HDAC Research, LLC Methods of inducing terminal differentiation
US7148257B2 (en) * 2002-03-04 2006-12-12 Merck Hdac Research, Llc Methods of treating mesothelioma with suberoylanilide hydroxamic acid
GB0205347D0 (en) * 2002-03-07 2002-04-24 Svanborg Catharina Biologically active complex
GB0210464D0 (en) * 2002-05-08 2002-06-12 Svanborg Catharina Therapeutic treatment
CA2529840A1 (en) * 2003-06-27 2005-01-06 Astellas Pharma Inc. Therapeutic agent for soft tissue sarcoma
EP1557665A1 (en) 2004-01-21 2005-07-27 CSEM Centre Suisse d'Electronique et de Microtechnique SA Electrode system for an electrochemical sensor
US20050187148A1 (en) * 2004-02-25 2005-08-25 Yoshinori Naoe Antitumor agent

Also Published As

Publication number Publication date
WO2006111550A2 (en) 2006-10-26
EP1872116A2 (en) 2008-01-02
US7875164B2 (en) 2011-01-25
US20080202944A1 (en) 2008-08-28
KR20080002964A (en) 2008-01-04
ATE528641T1 (en) 2011-10-15
CN101163966A (en) 2008-04-16
CN101163966B (en) 2012-01-11
WO2006111550A3 (en) 2007-01-25
EP1715334A1 (en) 2006-10-25

Similar Documents

Publication Publication Date Title
EP1872116B1 (en) Method using an electrochemical sensor and electrodes forming said sensor
Belmont et al. Mercury-plated iridium-based microelectrode arrays for trace metals detection by voltammetry: optimum conditions and reliability
US6144871A (en) Current detecting sensor and method of fabricating the same
CN101189507B (en) Electrochemical sensor
JP5659222B2 (en) Amperometric electrochemical sensor and manufacturing method thereof
Berduque et al. Voltammetric characterisation of silicon-based microelectrode arrays and their application to mercury-free stripping voltammetry of copper ions
US6478950B1 (en) Sensing liquids in oil well using electrochemical sensor
EP2737308B1 (en) Device for measuring the free chloride content of water
EP2675941B1 (en) Method for activating a doped diamond electrode
WO2009083482A1 (en) Method for detecting changes in water quality
CA2377947A1 (en) Micro reference electrode
Pinto et al. Antibiofouling strategy for optical sensors by chlorine generation using low-cost, transparent and highly efficient electrodes based on platinum nanoparticles coated oxide
Ivanovskaya et al. Electrochemical roughening of thin-film platinum for neural probe arrays and biosensing applications
EP3224607B1 (en) Electrochemical sensor comprising boron doped diamond electrode
EP0780684A1 (en) Reliable integrated electrochemical microsensors and microsystems for the direct chemical analysis of compounds in complex aqueous media
WO2011064265A1 (en) Electrochemical device for determining antioxidant properties of the skin
WO2002095387A1 (en) Electrode system for electrochemical sensor
WO2008012197A1 (en) Electrochemical system for assaying a biological compound by an enzyme
EP1557665A1 (en) Electrode system for an electrochemical sensor
EP2502059B1 (en) Method of dosing nitrates and/or nitrites in neutral environment
WO2006108759A1 (en) Method for voltametric electrochemical analysis and implementing device therefor
FR2567268A1 (en) METHOD AND ELECTRODE FOR MEASURING ENZYMATIC CONCENTRATIONS AND METHOD FOR PREPARING SUCH AN ELECTRODE
JP2012047691A (en) Method for manufacturing biosensor
FR2975493A1 (en) METHOD FOR DETERMINING NITRATES AND / OR NITRITES IN A NEUTRAL ENVIRONMENT

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20071031

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

DAX Request for extension of the european patent (deleted)
GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 602006025061

Country of ref document: DE

Effective date: 20111208

REG Reference to a national code

Ref country code: NL

Ref legal event code: VDEP

Effective date: 20111012

RAP2 Party data changed (patent owner data changed or rights of a patent transferred)

Owner name: HACH LANGE SARL

Owner name: ADAMANT TECHNOLOGIES SA

LTIE Lt: invalidation of european patent or patent extension

Effective date: 20111012

REG Reference to a national code

Ref country code: AT

Ref legal event code: MK05

Ref document number: 528641

Country of ref document: AT

Kind code of ref document: T

Effective date: 20111012

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120212

REG Reference to a national code

Ref country code: IE

Ref legal event code: FD4D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120113

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120213

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120112

Ref country code: IE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

26N No opposition filed

Effective date: 20120713

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 602006025061

Country of ref document: DE

Effective date: 20120713

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120123

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20130429

Year of fee payment: 8

Ref country code: GB

Payment date: 20130429

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20130506

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20111012

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120419

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20060419

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20140419

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20141231

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140419

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20141008

Year of fee payment: 9

Ref country code: DE

Payment date: 20141015

Year of fee payment: 9

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140430

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 602006025061

Country of ref document: DE

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20151103

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20150430

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20150430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140430